[INTERNAL] Revert "Bump yargs from 13.3.0 to 14.0.0"

This reverts commit 5a8f46e.

Breaking change "do not allow additional positionals in strict mode"
affects "ui5 serve"

Before:
"ui5 serve foo" => Starts server

After 5a8f46e:
"ui5 serve foo" => Displays help followed by "Unknown argument: foo"

Author: RandomByte

npm-shrinkwrap.json

@@ -113,7 +113,7 @@
 		"supports-color": "^7.0.0",
 		"treeify": "^1.0.1",
 		"update-notifier": "^3.0.1",
-		"yargs": "^14.0.0"
+		"yargs": "^13.3.0"
 	},
 	"devDependencies": {
 		"ava": "^2.4.0",